How does this medication work? What will it do for me?

Indinavir belongs to the class of antiretroviral medications called protease inhibitors. It is used in combination with other HIV medications to treat the infection caused by the human immunodeficiency virus (HIV). HIV is the virus responsible for acquired immune deficiency syndrome (AIDS). HIV infection destroys CD4 (T) cells, which are important to the immune system. The immune system helps fight infections.

Indinavir works by blocking the action of protease, an enzyme which the virus needs to multiply. Indinavir does not cure AIDS and does not prevent it from being spread to others. It does slow further growth or reproduction of HIV when used in combination with other drugs, and it seems to slow down the destruction of the immune system. This may help to delay the development of problems that are related to AIDS or HIV disease.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

How should I use this medication?

The recommended adult dose of indinavir is 800 mg taken with water every 8 hours.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

In order to get the most benefit from indinavir, it should be taken one hour before or 2 hours after a meal. It may also be taken with liquids other than water, such as skim milk, juice, coffee, or tea; or with a snack (e.g., dry toast with jelly, apple juice, or corn flakes with skim milk and sugar). Do not take indinavir with meals that are high in fat or calories, as this will reduce your body's ability to absorb the medication, which reduces its effectiveness.

Indinavir must be taken at 8 hour intervals to ensure there is enough medication in the bloodstream to be effective.

It is important to drink extra fluids while taking this medication so that more urine is passed and to prevent kidney stones from developing. Discuss with your doctor how much fluid you should drink. Usually about 1.5 litres (48 ounces) of fluid per day is recommended.

It is important to take this medication on a regular basis as prescribed by your doctor. The doses should be spaced as close to every 8 hours as possible. If you miss a dose by more than 2 hours, do not take it later in the day. Simply continue to follow your usual schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

If you forget many doses in a row, talk to your doctor about how to resume dosing.

Indinavir should be stored at room temperature in a tightly closed container and protected from moisture. Keep out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Stop taking the medication and seek immediate medical attention if any of the following occur:

signs of a heart attack, e.g.:

chest pain or pressure

nausea and vomiting

pain extending through shoulder and arm

sweating

signs of a serious allergic reaction, e.g.:

abdominal cramps

difficulty breathing

nausea and vomiting

swelling of the face and throat

signs of a severe skin reaction, e.g.:

a rash combined with fever or discomfort

a rash covering a large area of the body

a rash that spreads quickly

blistering

peeling

signs of pancreatitis, e.g.:

abdominal pain on the upper left side

back pain

chills

fever

nausea

rapid heartbeat

swollen abdomen

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Bleeding problems: Indinavir may put people with hemophilia at a higher risk of bleeding while taking this medication. If you have hemophilia, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Indinavir may also reduce the number of platelets in the blood. Platelets are responsible for forming clots. If you experience unusual bruising or bleeding, bleeding gums, unusual nosebleeds, stools that look like coffee grounds, or blood in your urine, contact your doctor immediately.

Diabetes: Indinavir may cause diabetes or increase blood sugar levels. If you have diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is required.

If you experience symptoms of diabetes, such as frequent urination or increased thirst, or a fruity odour to your breath, contact your doctor.

Fat redistribution: Over time, this medication may change how fat is distributed in your body and may change your body shape. You may notice increased fat in the upper back and neck, on the breast, and around the back, chest, and stomach area; or loss of fat from the legs, arms, and face. The long-term effects of this are not known.

Immune reconstitution syndrome: This medication may cause immune reconstitution syndrome, where signs and symptoms of inflammation from previous infections appear. These symptoms occur soon after starting anti-HIV medication and can vary. They are thought to occur as a result of the immune system improving and being able to fight infections that have been present without symptoms (such as pneumonia, herpes, or tuberculosis). Report any new symptoms to your doctor immediately.

Kidney function: Indinavir can cause kidney stones. To reduce the possibility of developing this painful side effect, it is advised that you drink 1.5 L of water each day. If you experience signs of kidney stones, such as sharp pain in the side or abdomen, blood in the urine or painful urination, contact your doctor as soon as possible.

If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Indinavir is removed from the body by the liver and may cause liver problems. If you have liver disease or decreased liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Stopping the medication: If you stop taking this medication, your HIV infection could get worse. Take the medication exactly as prescribed by your doctor, and do not stop taking the medication without checking with your doctor first.

Pregnancy: The safety and effectiveness of using indinavir during pregnancy are not known. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if indinavir passes into breast milk. Women with HIV infection are cautioned against breast-feeding because of the risk of passing HIV to a baby who does not have the infection, since the virus can be transmitted through breast milk.

Children: Studies have shown that children are more likely to develop kidney stones than adults if they take indinavir. Indinavir is not recommended for children.

Seniors: The safety and effectiveness of indinavir have not been established for seniors.

What other drugs could interact with this medication?

There may be an interaction between indinavir and any of the following:

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

stop taking one of the medications,

change one of the medications to another,

change how you are taking one or both of the medications, or

leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.